
crc_table16 = [0x0000,0x8005,0x800f,0x000a,0x801b,0x001e,0x0014,0x8011,0x8033,
               0x0036,0x003c,0x8039,0x0028,0x802d,0x8027,0x0022,0x8063,0x0066,
               0x006c,0x8069,0x0078,0x807d,0x8077,0x0072,0x0050,0x8055,0x805f,
               0x005a,0x804b,0x004e,0x0044,0x8041,0x80c3,0x00c6,0x00cc,0x80c9,
               0x00d8,0x80dd,0x80d7,0x00d2,0x00f0,0x80f5,0x80ff,0x00fa,0x80eb,
               0x00ee,0x00e4,0x80e1,0x00a0,0x80a5,0x80af,0x00aa,0x80bb,0x00be,
               0x00b4,0x80b1,0x8093,0x0096,0x009c,0x8099,0x0088,0x808d,0x8087,
               0x0082,0x8183,0x0186,0x018c,0x8189,0x0198,0x819d,0x8197,0x0192,
               0x01b0,0x81b5,0x81bf,0x01ba,0x81ab,0x01ae,0x01a4,0x81a1,0x01e0,
               0x81e5,0x81ef,0x01ea,0x81fb,0x01fe,0x01f4,0x81f1,0x81d3,0x01d6,
               0x01dc,0x81d9,0x01c8,0x81cd,0x81c7,0x01c2,0x0140,0x8145,0x814f,
               0x014a,0x815b,0x015e,0x0154,0x8151,0x8173,0x0176,0x017c,0x8179,
               0x0168,0x816d,0x8167,0x0162,0x8123,0x0126,0x012c,0x8129,0x0138,
               0x813d,0x8137,0x0132,0x0110,0x8115,0x811f,0x011a,0x810b,0x010e,
               0x0104,0x8101,0x8303,0x0306,0x030c,0x8309,0x0318,0x831d,0x8317,
               0x0312,0x0330,0x8335,0x833f,0x033a,0x832b,0x032e,0x0324,0x8321,
               0x0360,0x8365,0x836f,0x036a,0x837b,0x037e,0x0374,0x8371,0x8353,
               0x0356,0x035c,0x8359,0x0348,0x834d,0x8347,0x0342,0x03c0,0x83c5,
               0x83cf,0x03ca,0x83db,0x03de,0x03d4,0x83d1,0x83f3,0x03f6,0x03fc,
               0x83f9,0x03e8,0x83ed,0x83e7,0x03e2,0x83a3,0x03a6,0x03ac,0x83a9,
               0x03b8,0x83bd,0x83b7,0x03b2,0x0390,0x8395,0x839f,0x039a,0x838b,
               0x038e,0x0384,0x8381,0x0280,0x8285,0x828f,0x028a,0x829b,0x029e,
               0x0294,0x8291,0x82b3,0x02b6,0x02bc,0x82b9,0x02a8,0x82ad,0x82a7,
               0x02a2,0x82e3,0x02e6,0x02ec,0x82e9,0x02f8,0x82fd,0x82f7,0x02f2,
               0x02d0,0x82d5,0x82df,0x02da,0x82cb,0x02ce,0x02c4,0x82c1,0x8243,
               0x0246,0x024c,0x8249,0x0258,0x825d,0x8257,0x0252,0x0270,0x8275,
               0x827f,0x027a,0x826b,0x026e,0x0264,0x8261,0x0220,0x8225,0x822f,
               0x022a,0x823b,0x023e,0x0234,0x8231,0x8213,0x0216,0x021c,0x8219,
               0x0208,0x820d,0x8207,0x0202]
def calc(msg):
    acc = 0x00
    for x in msg:
        acc = (acc >> 8) ^ crc_table16[(acc ^ ord(x)) & 0xff]
    return acc
